Various types of reactive polymers have been developed and are known in the art. These reactive polymers are produced by a number of well known methods. These methods generally require the reactive polymers to be produced in a successive series of steps. U.S. Pat. No. 3,974,303, issued to Iwase et al., discusses reactive polymers to use in a specific method of application, and generally teaches how to make such polymers in two separate batches.
In a typical methodology, a first polymeric product is produced that carries reactive functional groups which can react in a subsequent modification reaction to give the reactive polymer. The first polymeric product is generally produced via a continuous, batch, or semi-batch process. The subsequent modification reaction is typically an addition or condensation reaction with a reactant that carries a functional group that can react with the reactive functional group of the first polymeric product to produce a reactive polymer. U.S. Pat. No. 4,064,161, issued to Lewis et al.; U.S. Pat. No. 4,208,313, issued to Lewis et al.; U.S. Pat. No. 4,845,012, issued to Seko et al.; U.S. Pat. No. 5,484,850, issued to Kempter et al. as well as WO 9109888, and WO 9325596, discuss making reactive polymers via batch processes.
U.S. Pat. No. 3,919,146, issued to Emmons; U.S. Pat. No. 4,233,362, issued to Novak et al.; U.S. Pat. No. 4,242,243, issued to Antonelli et al., U.S. Pat. No. 4,303,565, issued to Tobias; and RE 31,309, issued to Antonelli et al. discuss unsaturated polymers where the backbone is formed via free radical mechanisms, and the side chains are unsaturated fatty acid derivatives, using long batch and semi-batch process times. The reaction route for these polymers involves 1) reaction of hydroxyl functional backbones with fatty acids, 2) reaction of carboxylic functional backbones with epoxy fatty acids, or 3) reaction of carboxylic functional backbones with hydroxyethyl fatty acid amine.
After the first polymeric product is produced, a number of processing steps are typically required to prepare the first polymeric product for the modification reaction with subsequent materials to form the reactive polymer. These steps include cooling, dissolving, flaking, milling or otherwise recovering/handling/processing the first polymeric product before it can undergo subsequent modification to form the reactive polymer.
Because of the difficulties above, most reactive polymers are produced via condensation mechanisms, and not free radical mechanisms. For example, the prior art discloses numerous examples of unsaturated polyester and urethane polymers where the reactive modifiers are added during or after the main chain step-polymerization.
There are also a number of patents involving anionic polymerization. Very little prior art teaches the production of the main chain polymer with a free radical mechanism. These prior art processes require two relatively long steps with intermediate polymer recovery in order to produce the final reactive polymer. Furthermore, such prior art methodologies teach batch processing methods. The economic advantages of using a single process are well known. U.S. Pat. No. 5,558,911, issued to Blum, teaches that a single continuous process is preferred to produce finished powder coatings by using a reactor and extruder in a series. However, the reference does not teach or suggest using such a layout to create unsaturated polymers. By requiring additional handling/recovery/processing of the first polymeric product prior to its subsequent modification, the cost and/or difficulties of producing reactive polymers is increased. A need remains for producing reactive polymers via a simple, cost effective method.